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使用ContentProContentProvider共享生词本数据

时间:2016-06-18 12:54:14      阅读:180      评论:0      收藏:0      [点我收藏+]

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自定义ContentProvider需要在项目清单中注册:

import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.provider.UserDictionary.Words;

public class DictProvider extends ContentProvider{
  private static UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);
  private static final int WORDS = 1;
  private static final int WORD = 2;
  private MyDatabaseHelper dbOpenHelper;
  static{
    //为UriMatcher注册两个Uri
    matcher.addURI(mediaprovidertest.Words.AUTHORITY, "words", WORDS);
    matcher.addURI(mediaprovidertest.Words.AUTHORITY, "word/#", WORD);
  }

  //第一次调用该DictProvider时,系统先创建DictProvider对象,并回调该方法
  @Override
  public boolean onCreate() {
    dbOpenHelper = new MyDatabaseHelper(this.getContext(),"myDict.db3",null,1);
    return true;
  }

  //查询数据的方法
  @Override
  public Cursor query(Uri uri, String[] projection, String selection,
    String[] selectionArgs, String sortOrder) {
    SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
    switch (matcher.match(uri)) {
      case WORDS:
        //执行查询
        return db.query("dict", projection,
            selection, selectionArgs, null, null, sortOrder);
      case WORD:
        //解析出想查询的记录ID
        long id = ContentUris.parseId(uri);
        String where =mediaprovidertest.Words.Word._ID+"="+id;
        //如果原来的where子句存在,拼接where子句
        if(selection != null && "".equals(selection)){
          where = where + " and "+selection;
        }
        return db.query("dict", projection, where, selectionArgs,
                null, null, sortOrder);

      default:
        throw new IllegalArgumentException("未知Uri:"+uri);
     }
  }

  //返回指定Uri参数对应的数据的MIME类型
  @Override
  public String getType(Uri uri) {
    switch (matcher.match(uri)) {
      //如果操作的数据是多项记录
      case WORDS:
        return "vnd.android.cursor.dir/org.crazyit.dict";
      //如果操作的数据时单项记录
      case WORD:
        return "vnd.android.cursor.item/org.crazyit.dict";
      default:
        throw new IllegalArgumentException("未知Uri:"+uri);
    }
  }

  //插入数据
  @Override
  public Uri insert(Uri uri, ContentValues values) {
    // 获得数据库实例
    SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
    //插入数据,返回行ID
    long rowId = db.insert("dict", mediaprovidertest.Words.Word._ID, values);
    //如果插入成功则返回uri
    if(rowId>0){
      //在已有的Uri的后面追加ID数据
      Uri wordUri = ContentUris.withAppendedId(uri, rowId);
      //通知数据已经改变
      getContext().getContentResolver().notifyChange(wordUri, null);
      return wordUri;
    }
    return null;
  }

  //删除数据的方法
  @Override
  public int delete(Uri uri, String selection, String[] selectionArgs) {
    SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
    //记录所删除的记录数
    int num = 0;
    //对Uri进行匹配
    switch (matcher.match(uri)) {
      case WORDS:
        num = db.delete("dict", selection, selectionArgs);
        break;
      case WORD:
        //解析出所需要删除的记录ID
        long id = ContentUris.parseId(uri);
        String where = mediaprovidertest.Words.Word._ID+"="+id;
        //如果原来的where子句存在,拼接where子句
        if(selection != null && selection.equals("")){
          where = where +" and "+selection;
        }
        num = db.delete("dict", where, selectionArgs);
        break;
    default:
      try {
        throw new IllegalAccessException("未知Uri:"+uri);
      } catch (IllegalAccessException e) {
        e.printStackTrace();
      }
    }
    //通知数据已经改变
    return num;
  }

  //修改数据的方法
  @Override
  public int update(Uri uri, ContentValues values, String selection,
        String[] selectionArgs) {
    SQLiteDatabase db = dbOpenHelper.getWriteDatabase();
    //记录所修改的记录数
    int num = 0;
    switch (matcher.match(uri)) {
      case WORDS:
        num = db.update("dict", values, selection, selectionArgs);
        break;
      case WORD:
        //解析出想修改的记录ID
        long id = ContentUris.parseId(uri);
        String where = mediaprovidertest.Words.Word._ID+"="+id;
        //如果原来的where子句存在,拼接where子句
        if(selection != null && selection.equals("")){
          where = where +" and "+selection;
        }
        num = db.update("dict", values, where, selectionArgs);
      default:
        throw new IllegalArgumentException("未知Uri:"+uri);
     }
    //通知数据已经改变
    getContext().getContentResolver().notifyChange(uri, null);
      return 0;
   }

}

使用ContentProContentProvider共享生词本数据

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原文地址:http://www.cnblogs.com/jiww/p/5595919.html

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